Suellen Herbster

Infection with some mucosal human papillomavirus (HPV) types is the etiological cause of cervical cancer and of a significant fraction of vaginal, vulvar, anal, penile, and head and neck carcinomas. DNA repair machinery is essential for both HPV replication and tumor cells survival suggesting that cellular DNA repair machinery may play a dual role in HPV biology and pathogenesis. Here, we silenced genes involved in DNA Repair pathways to identify genes that are essential for the survival of HPV-transformed cells. We identified that inhibition of the ATM/CHK2/BRCA1 axis selectively affects the proliferation of cervical cancer-derived cell lines, without altering normal primary human keratinocytes (PHK) growth. Silencing or chemical inhibition of ATM/CHK2 reduced the clonogenic and proliferative capacity of cervical cancer-derived cells. Using PHK transduced with HPV16 oncogenes we observed that the effect of ATM/CHK2 silencing depends on the expression of the oncogene E6 and on its ability to induce p53 degradation. Our results show that inhibition of components of the ATM/CHK2 signaling axis reduces p53-deficient cells proliferation potential, suggesting the existence of a synthetic lethal association between CHK2 and p53. Altogether, we present evidence that synthetic lethality using ATM/CHK2 inhibitors can be exploited to treat cervical cancer and other HPV-associated tumors.

Human papillomavirus (HPV)-induced carcinogenesis comprises alterations in the expression and activity of matrix metalloproteinases (MMP) and their regulators. Reversion-inducing Cysteine-rich protein with Kazal motifs (RECK) inhibits the activation of specific metalloproteinases and its expression is frequently lost in human cancers. Here we analyzed the role of RECK in cervical carcinogenesis. Cervical cancer derived cell lines over expressing RECK were used to determine tumor kinetics as well as, cellular, immune and molecular properties in vivo. Besides, we analyzed RECK expression in cervical cancer samples. RECK over expression (RECK+) delayed tumor growth and increased overall survival in vivo. RECK+ tumors displayed an increase in lymphoid-like inflammatory infiltrating cells, reduced number and viability of tumor and endothelial cells and lower collagenase activity. RECK+ tumors exhibited an enrichment of cell adhesion processes both in the mouse model and cervical cancer clinical samples. Finally, we found that lower RECK mRNA levels were associated with cervical lesions progression and worse response to chemotherapy in cervical cancer patients. Altogether, we show that increased RECK expression reduced the tumorigenic potential of HPV-transformed cells both in vitro and in vivo, and that RECK down regulation is a consistent and clinically relevant event in the natural history of cervical cancer.

Introduction: The main risk factor for the development of cervical cancer (CC) is persistent infection by human papillomavirus (HPV) oncogenic types. In order to persist, HPV exhibits a plethora of immune evasion mechanisms. PI3/Elafin (Peptidase Inhibitor 3) is an endogenous serine protease inhibitor involved in epithelial protection against pathogens. PI3/Elafin’s role in CC is still poorly understood. Materials and Methods: In the present study, we addressed PI3/Elafin protein detection in 123 CC samples by immunohistochemistry and mRNA expression in several datasets available at Gene Expression Omnibus and The Cancer Genome Atlas platforms. Results: We observed that PI3/Elafin is consistently downregulated in CC samples when compared to normal tissue. Most of PI3/Elafin-positive samples exhibited this protein at the plasma membrane. Besides, high PI3/Elafin expression at the cellular membrane was more frequent in in situ stages I + II than in invasive cervical tumor stages III + IV. This indicates that PI3/Elafin expression is gradually lost during the CC progression. Of note, advanced stages of CC were more frequently associated with a more intense PI3/Elafin reaction in the nuclei and cytoplasm. Conclusion: Our results suggest that PI3/Elafin levels and subcellular localization may be used as a biomarker for CC severity.